Freeze-thaw cycles and road salt make concrete flatwork one of the most commonly repaired elements in Ontario homes. Here’s the repair decision framework.
Failure types:
- Scaling/spalling: Surface deterioration from deicing salt + freeze-thaw. Eventually progresses through full slab thickness.
- Settlement/heave: Differential movement from frost, sub-base erosion, or tree roots.
Repair hierarchy:
1. Crack injection ($150-$400/crack):
Polyurethane (flexible, good for moving cracks) or epoxy (rigid, for stable cracks). Not appropriate for cracks in slabs with ongoing differential settlement.
2. Slab lifting ($300-$1,200/section):
- Mudjacking (cement-soil slurry): $300-$800/section. Heavy, can re-settle.
- Polyurethane foam lifting: $500-$1,200/section. Lighter, faster curing, pricier.
Both limited to structurally sound slabs with minimal cracking.
3. Resurfacing ($4-$8/sq ft):
Polymer-modified overlay for surface-scaled slabs. Does not fix structural cracks or settlement. Will follow any future movement.
4. Full replacement:
Required for: differential settlement, scaling through 1/3+ of thickness, salt penetration to rebar depth.
Replacement costs (GTA 2026):
- Walkway (4" slab): $10-$18/sq ft
- Driveway (4" slab): $12-$20/sq ft
- Garage floor: $8-$14/sq ft
- Exposed aggregate/stamped: add $3-$8/sq ft
- Entry steps (4-riser): $1,500-$3,500
Concrete contractor referrals at home.renovation.reviews